Economic vulnerability contributes to HIV risk among U.S. racial and ethnic minorities living in concentrated areas of poverty. In particular, African-Americans disproportionately account for nearly half of all new HIV diagnoses in the U.S. and are more likely than other U.S. racial and ethnic minorities to live in high poverty and high HIV prevalence communities. Of concern is that young adults have the highest HIV rates of all U.S. age groups and make up an increasing proportion of the urban homeless and unemployed, factors often associated with HIV and other adverse health and social outcomes. Limited economic resources can create a short-term imperative among the poor to engage in high-risk survival strategies that increase HIV vulnerability. Poverty can also lead to a loss of hope and agency that diminish motivations to avoid exposure to future infection. Microenterprise development may sustain longer-term effects on economic drivers of HIV risk than traditional employment and cash incentive approaches. Yet, few microenterprise interventions have been adapted for low-income African-American young adults. Furthermore, behavioral economics may enhance the delivery of microenterprise strategies for HIV prevention by deepening our understanding of economic contexts and motivations associated with sexual risk-taking. As such, this proposed NIMH Mentored Career Development Award (K01) is uniquely timed to contribute to the growing field of economic-strengthening and HIV prevention. Guided by asset and behavioral economic theories, Dr. Jennings' goal is to develop and test the feasibility and pilot efficacy of an enhanced microenterprise intervention for HIV prevention among high-risk African-American young adults who are marginally housed, unemployed, and out of school. The intervention is hypothesized to reduce sexual risk behaviors by: providing skills on safer sex strategies; increasing assets that minimize economic stressors and motivate protective sexual behaviors; improving psychosocial attributes that enhance safer sex self-efficacy and employability in lieu of survival strategies; and shifting intertemporal rewards for safer sex strategies. The specific aims of this proposal are: 1) in a pre-design phase, qualitatively examine motivations associated with HIV protective and risky sexual behaviors using the behavioral economic principles of delay discounting, loss aversion, and endowment effect; 2) to develop a HIV prevention microenterprise intervention adapted from international models and incorporating mobile-based behavioral economic nudges; and 3) to pilot test the feasibility and longitudinal efficacy of an enhanced microenterprise intervention in reducing risky sexual behaviors in an RCT. The primary outcome will be frequency of unprotected sexual acts. Secondary outcomes will include additional sexual risk behaviors, attitudes on costs and rewards of HIV protective and risky sexual behaviors, psychosocial attributes, entrepreneurial activity, and economic outcomes. Longitudinal analyses will be used to estimate differences in the level and trend of repeated measures over time. Guided by a multidisciplinary team of experts in microfinance, HIV prevention science, economic empowerment, behavioral economics, biostatistics, and mobile health, Dr. Jennings' training objectives for this proposed career development award are to gain skills in: 1) behavioral economic methods and theories; 2) development and testing of microenterprise interventions; 3) statistics for longitudinal data analyses; and 4) use of mobile technology in health-related research. The proposed research will provide training and mentored research experience to prepare Dr. Jennings for an independent research career aiming to reduce HIV vulnerability through economic-strengthening interventions among urban poor African-American and other racial and ethnic minority young adults in the U.S. and worldwide.